近70 a北太平洋夏季SST及其与西太副高变化特征的相关

基于1948—2018年美国国家海洋和大气管理局(NOAA)重建海面温度(ERSSTv5)资料集，采用经验正交函数(EOF)分解和交叉小波分析等统计学方法，对北太平洋地区近70 a海表温度(SST)、西太平洋副热带高压(WPSH)的变化特征及其相关性进行分析。第一模态体现了SST显著的年际变化厄尔尼诺-南方涛动(ENSO)现象和显著的年代际变化北太平洋年代际振荡(PDO)现象。将WPSH强度距平指数和面积距平指数的均值定义为WPSH综合指数。WPSH综合指数总体呈上升趋势; 1977年之前，WPSH强度逐渐减小且振幅较小; 1977年之后，WPSH强度逐渐增大且振幅强度较大。通过合成分析发现，WPSH异常偏强年份对应西北太平洋大部分地区的SST显著偏暖，WPSH异常偏弱年份对应西北太平洋大部分地区的SST显著偏冷。将其与NOAA的月气候指标的Ni?o3.4和PDO指数分别进行交叉小波谱分析，得出:北太平洋SST的年际信号、年代际信号均与WPSH的变化有很明显的相关，WPSH强度和太平洋中部SST存在显著的4~5 a的年际正相关，且随着时间的后移，SST的变化超前于WPSH的变化。 

SUMMER SST IN THE NORTHWEST PACIFIC IN THE PAST 70 YEARS AND ITS CORRELATION WITH THE VARIATION OF THE WESTERN PACIFIC SUBTROPICAL HIGH

Based on the National Oceanic and Atmospheric Administration (NOAA) reconstructed sea surface temperature (ERSSTv5) dataset from 1948 to 2018, the characteristics of and correlations between the variations in sea surface temperature (SST) and the western Pacific subtropical high (WPSH) in the last 70 years are analysed using statistical methods such as empirical orthogonal function (EOF) decomposition, and cross-wavelet analysis. The results show that the first mode reflects the significant interannual variation of SST, the El Ni?o-Southern Oscillation (ENSO), and the significant interdecadal variation of the North Pacific decadal oscillation (PDO). The mean of the WPSH intensity anomaly index and area anomaly index is defined as the WPSH composite index, and the results show that the WPSH composite index is generally on the rise. Before 1977, the WPSH intensity gradually decreased and the amplitude was small. After 1977, the WPSH intensity gradually increased and the amplitude intensity was large. Through synthetic analysis, it is found that the year with relatively strong WPSH corresponds to significantly warmer SST in most parts of the Northwest Pacific, and the year with relatively weak WPSH anomaly corresponds to significantly colder SST in most parts of the Northwest Pacific. Using cross-wavelet spectrum analysis of the WPSH composite index and the NOAA's monthly climate index Ni?o3.4, and the analysis of the WPSH and PDO, the present study finds that the inter-annual and inter-decadal signals of the North Pacific SST are significantly related to the variations of the WPSH. The WPSH intensity and the SST in the central Pacific Ocean has a significant interannual positive correlation between 4-5a, and the SST varies before the WPSH does.